Errani eliminated from US Open
"I don't know. I think it was the pressure. Everything was difficult for me," Xinhua quoted Errani as saying after the match Thursday.
Errani, who moved up to the fourth seed because of Maria Sharapova's withdrawal, admitted that she was influenced by the move.
"I know all the players expecting from me and I would like to know how to do it. But you have to pass it on yourself and it is never the same that somebody is telling you and not that you are passing the moment," said the fourth seeded Errani.
The 83rd-ranked Pennetta wasn't an ideal opponent for Errani as the 31-year-old had won three of the previous five meetings.
The match went in rhythm for Penneta from the first game where Errani made too many unforced errors. Errani broke back in the second game but Pennetta won four straight games to establish a 5-1 lead and took the first set 6-3.
Errani was unable to recover in the second set, dropping five straight games after 1-1 to lose the match.
"I'm not the kind of player who can go there and score aces and winners. If the ball is going in then I'm doing good. For me it is to go there and fight. If I feel that I'm not fighting good because of too much pressure or not feeling good with myself then I won't play," said Errani about her play style.
Most other seeds did well in their matches.
Top seed Serena Williams, second seed Victoria Azarenka, sixth seed Caroline Wozniacki and several others won easy matches to reach the next round.
China's 27-year-old Peng Shuai had a tough match against former champion Svetlana Kuznetsova 1-6, 6-4, 4-6 to miss the third round.
Peng met trouble at the beginning of the first set, finding herself 0-5 down before claiming her first game. The 27th seeded Russian held serve in the seventh game to knock down the first set 6-1.
The Chinese seemed to have become a different player in the second set. The two players had eight close games in which neither was able to break. Peng finished an important break in the ninth game and then served out the set 6-4.
The final set went on (2-2) and Peng took a chance to break once but Kuznetsova broke back in the following game to level the scores.
Peng had an unfortunate injury when she was down 4-5. The Chinese couldn't recover from the injury, losing the set 4-6 after saving one match point.
In the men's singles, both second seed Rafael Nadal and seventh seed Roger Federer were able to advance to the next round.